Managing Symphylans with Rotation and Biopesticides

Commodities

• Agronomic: potatoes
• Vegetables: broccoli, greens (leafy)

Practices

• Crop Production: crop rotation
• Pest Management: biorational pesticides, botanical pesticides, economic threshold, integrated pest management, prevention, traps
• Production Systems: organic agriculture

Symphylans (Scutigerella immaculata Newport) are a persistent soil pest that affects many fresh vegetable and seed crops in Oregon’s Willamette Valley, resulting in poor stand establishment and economic damage. They are consistently identified as a major pest in the maritime Pacific Northwest, particularly in fields with fine-textured soils, high organic matter, and irrigation, which are common here. This project will demonstrate innovative monitoring and management strategies at OSU and on organic fresh vegetable and specialty seed farms. Our objectives are to: 1) Increase the adoption of symphylan monitoring; 2) Strengthen confidence in suppressive and tolerant crops; 3) Demonstrate judicious and effective use of biopesticides for symphylan management; and 4) Expand symphylan management knowledge among a broader audience.

We developed this project in close consultation with growers at a workshop in February 2024 and individual interviews. We will demonstrate symphylan bait sampling, the effectiveness of suppressive crops, and promising biopesticides identified in previous WSARE-funded projects and in Kaur’s ongoing research.

We propose a combination of OSU and on-farm demonstrations and field days that include interactive symphylan monitoring and management activities and peer-to-peer conversations around symphylan management. OSU demonstrations will include all components (monitoring, suppressive and tolerant crops, and biopesticides). Farmers will choose management methods based on monitoring results from their farm. This work will be shared more widely at an intensive symphylan management workshop and at grower conferences. Written information will also be distributed through newsletter articles and a new symphylan management Extension publication.

We will measure project outcomes with surveys at field days and workshops that evaluate knowledge gain and intention to adopt the research-based practices we promote. Collaborator interviews, notes from peer-to-peer conversations and the level of engagement with workshop and field day activities will provide qualitative evaluation information to complement survey results.

1. Increase adoption of symphylan monitoring. Bait
   sampling is effective but nuanced. When used correctly it can
   identify hot spots and guide management decisions. We will
   monitor an OSU demonstration site and collaborator’s fields for
   symphylans and associated predators and interpret results to
   guide crop rotations (e.g., susceptible, tolerant or
   suppressive crop) and biopesticide choices.
2. Strengthen confidence in the use of suppressive and
   tolerant crops. We will recommend areas to plant
   suppressive or tolerant crops based on monitoring results.
   Choices will vary between farms and may include potato cash
   crops, potatoes terminated early as a pest management cover
   crop, grass or cereal cover crops, or other suppressive plants
   identified in Kaur’s research. We will develop a list of
   suppressive and tolerant crops based on a review of scientific
   literature and the experiences of collaborators.
3. Demonstrate judicious and effective use of biopesticides
   for symphylan management. Drawing on Kaur’s ongoing
   insecticide efficacy trials, we will demonstrate promising
   biopesticides at OSU. We will present biopesticide options to
   collaborators monitor results on their farms. All our
   collaborators are certified organic or use organic methods, so
   this work will focus on NOP-compliant biopesticides. Some
   collaborators are reluctant to use any pesticides.
4. Increase symphylan management knowledge among a wider
   audience using the PAMS approach: Prevention, Avoidance,
   Monitoring, and Suppression (Coble 2003). We will host a
   wide range of events to share knowledge from this and related
   projects and publish at least one newsletter article and one
   peer-reviewed Extension publication.